Why Is My “Check Engine” Light On?

By Product Expert | Posted in Tips and Tricks on Friday, January 11th, 2019 at 11:38 am
A dirty white gloved hand working on a car engine.

More formally known as Malfunction Indicator Lamp (MIL), the “check engine” light is primarily monitors a car’s emissions system. But according to Dan Edmunds, director of vehicle testing for Edmunds.com, “the engine and the emission control system are so interlinked that the health of the emission control system is a good indication of the general health of the car’s engine.”

With this in mind, resist that common human urge to ignore the light. If your Check Engine light is illuminated and doesn’t turn off on its own in a short period of time, it’s best to get it looked at promptly; especially if the light is flashing, which indicates a more serious problem. Below we have the five most common causes for an illuminated Check Engine light.

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Pair of hands uses a screwdriver to tighten a screw in a a car engine.Five Most Common Reasons Your Check Engine Light Is On

  1. Oxygen Sensor
  2. Loose Gas Cap
  3. Catalytic converter
  4. Mass airflow sensor
  5. Spark plug wires

False Alarms

It’s worth noting that the light does malfunction sometimes. It’s recommended that the first thing to check when your engine light comes on is your gas cap, which can set the light off if loose. Check your gas cap is tight, and tighten if needed. After doing so, it will still take a short time before the light turns off.

The light can also turn on due to humidity or other factors, but should turn off on its own after a short time in these cases.

In addition, drivers often confuse the Check Engine light with the Service Required light; the latter simply means the car is due for an oil change or other routine service. So before you take the car in, make sure that you’re looking at the right light.

Finding the Problem Yourself

If you want to get an idea of what’s wrong yourself before taking your vehicle into a mechanic, there are many inexpensive devices available at auto parts stores that allow you to get information about the problem directly from your vehicle. Plug the device into your vehicle’s standardized Onboard Diagnostics (OBD) port and see what code comes up on the device. The OBD port is usually located under the steering column and should be fairly easy to access. After getting the code, you can search to find the issue it corresponds with online.

However, be careful of jumping to conclusions and applying fixes yourself. For example, if the code indicates a certain sensor is broken, it may be that the sensor is totally fine but the wires leading to it are damaged. For assistance in fixing the problem yourself, consult your car manual, which can often be found online. 

4 Responses to “Why Is My “Check Engine” Light On?”

  1. Eve Wilson says:

    Malfunctions in different components of the emission control system like catalytic converter or oxygen sensor are solely responsible for the appearance of check engine light and a person should not ignore the appearance of such warning signs. The complications associated with the concerned components need to be identified and repaired in time to keep the vehicle in working order. For more information, visit https://entirelyxmotors.com/contact-us/

  2. Sam Robinson says:

    I appreciate the information given in this article about the possible reasons behind the appearance of the check engine light. Some people have no idea about the possible reasons behind the appearance of the check engine light which could cost them a lot. Such warning signs should not be ignored. The reason behind the appearance of such warning signs needs to be identified and repaired immediately. To know more, https://www.professionalautomotive.com/engine-repair

  3. Jim McAdams says:

    Couldn’t agree more…
    Issues in certain components of the vehicle including the mass airflow sensor could be responsible for the appearance of the check engine light.
    It should not be overlooked. Damages done to those components should be repaired immediately. Regular inspection of different components of the vehicle including different components of the emission control system is really essential.

  4. My aunt has noticed that she is having a lot of problems with her car engine because she has heard a lot of clanking and banging from inside. Getting some help from a professional to take a look at it could be really nice for her. I’ll be sure to tell her about how she should make sure that the light isn’t turned on because of the humidity and the gas cap.

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